Great idea.

I suspect the cost of maintaining a rubber coating on the concrete barriers would preclude most government agencies fron implementing it. Some barriers are hit nearly every day. If you had to close part of the lanes each day to fix the rubber people would fume.

Those grassy medians and concrete barriers are designed to be low maintenance ways of keeping oncoming traffic out of your lane on a highway. And there are already crumple zone barriers on the obstructions on a highway.

Things are a bit different on a racetrack. On a track all the cars are going roughly the same speed and direction. They are only there for a few days a year for a limited time. Racetracks are shorter than highways and it is easy to see where the problem areas are.

Caltrans (Calif highway department) looked at it and decided it caused cars to bounce back into traffic. They went with crushable steel rails in most places.

digital guidance could sort out that problem. Do they coat the sides of railway bridges with rubber? No, because they pretty much never go off course - why are cars going off course on roads where the course is +/- 1 foot to the lane center and a speed. Then 2 low power antennas could be cut to the center of every road-lane, and cars fitted with a small pickup that would guide the car to the dead center of the lane every time a human took their hands off the wheel. These same antennas could transmit the speed, and the user could program the exit - return driver control at exit 41 - then cars would go offcourse only very veryrarely like rail does (at least on highways and interstates). For the minimal interference of cutting a grove in to the road, a system that could radically improve roads safety gets humans out of boring mechanical tasks that require constant attention to accuracy.